This invention relates in general to aquarium devices and in particular to aquarium water purifiers.
In certain applications, it is important for water which may be utilized in a process step to be treated or in some manner sterilized. One particular application is with aquariums, and one particular method is to employ ultraviolet radiation directed at a flow stream of water. Ultraviolet radiation, assuming that there is a sufficient wattage level and duration of exposure by the water, is effective to destroy harmful water-born algae, bacteria, fungus, yeasts and viruses.
The following listed patents disclose various designs which have been conceived for sterilizing or purifying water.
______________________________________ Patent No. Patentee Issue Date ______________________________________ 2,669,661 Riddiford et al. 2/16/54 2,578,414 Foulds 12/11/51 3,683,177 Veloz 8/08/72 4,033,719 Conn et al. 7/05/77 3,971,947 Lambert et al. 7/27/76 ______________________________________
Riddiford et al. discloses an apparatus for treating water wherein the length of exposure to the ultraviolet radiation is controlled and the flow control structural members are readily accessible for cleaning and other servicing.
Foulds discloses a liquid irradiating apparatus wherein all the liquid passing through the apparatus is forced at some time during its passage to traverse a section of very shallow depth, while being exposed to ultraviolet radiation.
Veloz discloses a device for sterilization of water which includes a flexible bag through which the water is pumped and is formed of a material transparent to ultraviolet radiation.
Conn et al. discloses an ultraviolet sterilizer for a recirculating water flow filter system in which the sterilizer includes a low power source of ultraviolet light. Means are employed to thin out an air-water recirculating sheet and the ultraviolet sterilizer is placed a small distance from the sheet in order to irradiate the mixture and create an ozone layer further sterilizing the recirculating mixture.
Lambert et al. discloses an ultraviolet water purifier which includes a plurality of ultraviolet lamps mounted in a cover extending over the purifier and above the water in the purifier with a parabolic reflector directing the rays of the lamp toward the body of water. The purifier is provided with a water inlet and a baffle adjacent thereto having an opening at is base to compel the water entering the purifier to flow directly downward and then to flow through a filter. A baffle plate disposed in the approximate center of the receptacle divides the receptacle into two compartments such that flow between these compartments must pass over the top of the baffle plate. This over-the-top passage assures exposure to the ultraviolet radiation.
Although these various designs and apparata involve the use of ultraviolet light, the only patent of particular relevancy to the subject invention is the Lambert et al. patent for its association with purifying the water of an aquarium. Aquariums are available in a variety of sizes and shapes and one critical consideration in the design of a filtering system as well as a purifying system is the volume of water contained within the aquarium. This water must be filtered and sterilized at a particular rate in order to keep the water clean and sanitary. The problem is one of circulating the entire tank at a certain frequency such as, for example, three tank fulls per hour so that based on the rate of bacteria growth, bacteria will not form in the water to a harmful level before the water is again drawn through the filtering and sterilizing system. Consequently, if there is a 20-gallon tank, the flow rate should be approximately 60 gallons per hour. However, if there is an 80-gallon tank associated with the aquarium, then the flow rate must be 240 gallons per hour. Consequently, when purchasing an aquarium, the filtering system associated with the aquarium must be correspondingly suitably sized. Due to the fixed sizes of the various flow apertures and passageways of the Lambert et al. patent, adaptability to different flow rate requirements is not achievable. Furthermore, since the filter system is included as part of the water purifyer device, the rate of flow across the filter is also controlled by the physical inlet and outlet sizes of the particular purifier device. A related aspect involving the purification of water by the use of ultraviolet radiation is to properly select a bulb wattage level which is sufficient to purify the water flow rate and to control the duration of exposure such that the water-born algae and bacteria can be killed. If the wattage level is too low or the duration of exposure time too short, complete purification will not occur. In the Lambert et al. patent, water from the aquarium is pumped in through tube 12 into inlet 23. From this point it circulates through the filter and then into compartments 34 and 35. The manner in which this water leaves these two compartments is by overflowing through opening 30 which is associated with bracket B and then out through outlet 21. In the event the flow rate is somewhat rapid, this particular design, utilizing baffles, introduces backup eddies and irregular flow patterns and permits certain portions of the circulating water to enter the water purifier chambers and then to be emptied back into the aquarium almost immediately, not allowing sufficient time for sterilization to occur by means of the ultraviolet light. It appears that the flow through filter screens 29 will occur over the entire height of the screen and thus water entering chamber 34 at the top of filter screens 29 would empty into the aquarium with virtually no exposure to the ultraviolet light. An improvement to this design would be to create an ultraviolet water purifier wherein there was an inlet at one end of the light fixture and an outlet at the opposite end such that water flow between inlet and outlet would have to circulate through and beneath the entire length of the ultraviolet light and, if desired, could not leave the purifier device without doing so. It would also be an improvement to the listed patents to provide an ultraviolet water purifier for use with an aquarium which could be readily adapted to either an outside power filter set up as well as an under-gravel filter system. It would also be an improvement to the designs disclosed by the listed patents to provide such an ultraviolet water purifier wherein various flow rates could be selectively controlled by means of changing the cross-sectional area of the low outlets and wherein the points of flow entry as well as the points of flow discharge from the ultraviolet water purifier could be selectively changed. These and related improvements are achieved by the invention which is disclosed herein.